Well production signal means

ABSTRACT

A well pumping unit which employs a walking beam carried on a saddle bearing which in turn is supported by a sampson post wherein a signal means which produces a signal on movement of a member of the signal means is connected to at least one of the walking beam, saddle bearing, and the main shaft of the gear box which drives the pumping unit. Operation of the pumping unit gives an indication by way of the signal means as to the position of the polished rod which is connected to the pumping unit.

United States Patent 11 1111 3,

Duke et al. Dec. 16, 1975 [5 WELL PRODUCTION SIGNAL MEANS 3,457,781 7/1969 Elliott 73/151 Inventors: Spencer E. Duke, G and; Ge a d 3,527,094 9/1970 Yew et al 73/151 L. Stevens, Houston, both of Tex. Primary ExamineFJerry W. M yr a d e [73] Assignee: Atlantic Richfield Company, Los Attorney, Agent, or Firm-Roderick W. MacDonald Angeles, Calif 22 Filed: June 15, 1972 [571 ABSTRACT A well pumping unit which employs a walking beam [21] App! 262341 carried on a saddle bearing which in turn is supported by a sampson post wherein a signal means which pro- 52 US. (:1. 73/151 duces a Signal on movement of a member Of the Signal [51] Int. C1. E21B 47/00 means is connected o at least one o the walking [58] Field of Search 713/ 151, 133 R beam, Saddle ring, an he m in h f of the g r box which drives the pumping unit. Operation of the [56] References Cit d pumping unit gives an indication by way of the signal UNITED STATES PATENTS means as to the position of the polished rod which is 2,107,151 2/1938 l-ligginson 1. 73/151 x connected to the pumpmg 2,163,665 6/1939 Carr et a1 73/151 1 Claim, 6 Drawing Figures [5 I I 0 I4 1 l 1 i Z imL I W 3 1 1* 2o 5 I8 IO ll ,.2 I ii 5 1| madam;

US. Patent Dec. 16,1975 Sheet1of2 3,926,047

FIG. 3

FIG.2

U.S. Patent Dec. 16,1975 Sheet20f2 3,926,047

WELL PRODUCTION SIGNAL MEANS BACKGROUND or THE INVENTION.

Numerous onshore wells are produced by utilizing a pumping unit which is connected to a polished rod. The

polished rod carries a string of sucker rods at the bottom of which is a downhole pump. The pumping unit moves the polished rod, sucker rods, and downhole pump up and down in the wellbore to pump oil to the surface of the earth. Literally, thousands of these pumping units are spread across the country, some of which are located in very remote places. Being a mechanical device which is exposed to the elements and which has a number of working parts on the surface of the earth as well as in the downhole pump itself, parts of the device wear thereby causing inefficient operation of the pumping unit. Some parts ultimately break thereby causing an involuntary shutdown of the unit.

Oftentimes, a pumping unit is simply run to failure after which it is fixed and then run until failure again. Many times a unit will, before failure, run for extended periods of time at very low efficiency. Therefore, it is desirable to be able to determine when a pumping unit is not running at peak efficiency thereby indicating wear in the pumping unit itself or in the downhole pump which needs attention even though the unit is still operating.

Accordingly, apparatus has been devised which, by way of one or more strain gauges, measures the load on the sucker rod string during the pumping cycle. The readout from this type of measurement is known as a load trace which shows the load on the sucker rod string in relation to time during each pumping cycle (i.e., one complete trip of the downhole pump, sucker rod string, polished rod, and associated surface pump apparatus from a given position of the pump to the opposite position of the pump and then back again). These strain gauge transducers can be placed at many places on the surface pumping unit such as on the walking beam or on the polished rod as fully and completely disclosed in US. Pat. No. 3,343,409, the disclosure of which is hereby incorporated herein by reference.

The load trace by itself is not as useful as it might be unless the position of the polished rod is known at the time the load is measured so that it is desirable to make a determination of the position of the polished rod in relation to time and this is known as a displacement trace.

When the load trace and displacement trace are matched as to a particular point in time, it can be determined what the load on the sucker rod string was and at what point in the pumping cycle that load occurred. From this type of information numerous data can be obtained which are quite valuable in determining whether a pumping unit is working efficiently. For example, mathematical models have been developed which can operate on this type of data to give an indication of the torque on the gear box of the pumping unit, the maximum and minimum stresses experienced by the polished rod during the pumping cycle, the horsepower used to produce a particular volume of fluid, the overall pumping efficiency, the friction in the sucker rods, tubing movement, the operating fluid level, and

so on.

As indicated in the above-cited US. Pat. No. 3,343,409, a displacement trace has normally been obtained by hooking a displacement transducer to the ducer being a cable-and-reel driven device with a constant tension rewind assembly so that as the polished rod movesup and down, the displacement transducer is activated by'the cable moving up and down with the polished rod thereby activating the reel which norm ally drives a potentiometer to produce a varying voltage signal.

Since a strain gauge transducer or load cell can be mounted elsewhere on the surface pumping unit than the polished rod, and since it is desirable for a longtermoperation not to have apparatus sitting around the wellhead and connected to the polished rod, particularly by a cable which moves up and down with the polished rod, it is highly desirable from both a safety and a permanency of installation point of view to obtain the displacement trace from a part of the surface pumping unit other than the polished rod. This way the polished rod is freed from all associated transducer equipment. This allows all transducer equipment to be placed in more innocuous places than by the wellhead and minimizes the likelihood of damage thereto by normal operations being carried on around the wellhead. Also, a permanent installation can be set up in a manner which requires a minimum of maintenance.

SUMMARY OF THE INVENTION According to this invention, displacement trace equipment is located at one or more points on the surface pump unit. These points are physically removed from the polished rod and wellhead. More specifically, displacement trace signal means apparatus is employed in association with the walking beam, saddle bearing, or main gear box shaft so that when a strain gauge load cell is, for example, employed on the walking beam, all transducer apparatus is removed from the vicinity of the polished rod and wellhead.

Accordingly, it is an object of this invention to provide a new and improved apparatus for monitoring the operation of a pumping unit. It is another object to provide a new and improved apparatus for automating the production of an oil field. It is another object to provide a new and improved apparatus for permanently monitoring a surface pumping units operation.

Other aspects, objects and advantages of this invention will be apparent to those skilled in the art from this disclosure and the appended claims.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a plan view of a conventional surface pumping unit.

FIG. 2 shows a partial section of the pumping unit of FIG. 1 with a displacement trace signal means mounted in accordance with this invention.

FIG. 3 is a plan view of the apparatus of FIG. 2.

FIG. 4 is a cross-section of other apparatus according to this invention.

FIG. 5 shows yet other apparatus according to this invention.

FIG. 6 shows a top view of the apparatus of FIG. 5.

More specifically, FIG. 1 shows the earth 1 having a well bore 2 drilled therein and on the surface of which is wellhead 3 of well bore 2. A sucker rod string 4 extends into well bore 2 and is connected to polished rod 5 by way of coupling 6;

Sitting on the earths surface is platform 7 which carries a gear box 8 that has a main shaft 9 extending therefrom. Gear box 8 is driven by a power means (not shown) which operates the entire pumping unit. Mem ber is connected to main shaft 9 and carries counter balance 11. Counter balance 11 is connected by way of Pittmans 12 to tail bearing 13. Tail bearing 13 is fixed to walking beam 14, the opposite end of which carries horsehead 15. A wire cable 16 is-connected between horsehead and the upper end of polished rod 5.

Walking beam 14 rests on saddle bearing 17 which in turn is supported by sampson post 18.

The apparatus according to this invention can be fixed to the surface pumping unit of FIG. 1 in a plurality of locations. A preferred location is represented by dotted line box 19 and is associated with the saddle bearing 17. Another suitable location is represented by dotted line box 20 which is attached to the underside of walking beam 14. Yet another location is represented by dotted line box 21 which rests on platform 7 in thevicinity of main shaft 9.

FIG. 2 shows a part of saddle bearing 17 to which is fitted a conventional bearing dust cover 22. Dust cover 22 rotates with saddle bearing 17 as horsehead 15 reciprocates up and down. Therefore, dust cover 22 rotates through a finite are such as as horsehead l5 reciprocates, for example, from its lowest point to its highest point.

Bracket23 is fixed to dust cover 22 and thereby rotates with saddle bearing 17. A displacement signal means 24 which produces a signal upon movement of a member of the signal means is carried by way of support 25 which is fixed to sampson post 18. In this particular embodiment of the invention, the member of signal means 24 which is movable is shaft 26. Shaft 26 is fixed to bracket 23 so that operation of the pumping unit causes movement of walking beam 14 and saddle bearing 17 which in turn rotates shaft 26 and generates a signal. The signal is transmitted by way of conduit 27 to conventional readout and/or control equipment such as a computer, recorder, and the like. The signal produced by signal means 24 is of a character which varies with the extent of movement of shaft 26 so that the position of the polished rod 5 can be determined at a given point in time by the character of the signal.

Signal means 24 can be any electric, sonic, mechanical, or magnetic device known in the art which will produce a signal whose character, e.g., magnitude, will vary with the extent of movement of shaft 26. Thus, a displacement trace can be obtained in relation to time and the particular position of the sucker rod at a given point in time can be determined and matched with the same point in time on the load trace. This gives the load on the polished rod in relation to the position of the polished rod at that specific point in time.

Signal means 24 can be any device which produces a signal of varying characteristics depending upon the extent of movement of shaft 26. The device need not employ a rotatable shaft. For example, the device could employ a movable member which slides into and out of the device or is moved laterally within the device rather than rotated. Numerous devices, be they electrical, sonic, magnetic, or the like, are available in commerce and known to those skilled in the art. One suitable device is known as an absolute position encoder of the 5V80 series, manufactured by BALDWIN Electronics Inc. of Little Rock, Arkansas. This encoder is an electrically operated device which can be made to count upwards as its shaft is rotated either clockwise or counterclockwise so that a varying output signal is obtained as the shaft of the encoder is rotated. Put another way, as the encoder input shaft is rotated, there will appear at the encoder output a sequence of unique binary words that absolutely define every shaft position. Suitable other devices can utilize a rotating plate with a plurality of varying sized apertures around the periphery thereof so that rotation of the plate admits greater amounts of light to a receiving device. This principle can also be employed sonically and magnetically. In the sonic case sound of a different pitch is obtained as a plate is rotated because of air passing through different sized apertures in the periphery of the plate. In the magnetic case magnets placed around the periphery of the rotating plate can be employed.

FIG. 3 is an end view of the apparatus of FIG. 2, and shows circular dust cover 22 carrying rectangular bracket 23.

FIG. 4 shows a portion of the pumping unit of FIG. 1 wherein the signal means 24 is located on the walking beam 14 instead of on saddle bearing 17.

Signal means 24 is fixed to walking beam 14 by way of support 30. Shaft 26 of signal means 24 is connected to a first elongate member 31, which can be a pipe, rod, or other suitable device, and which has opposing first and second ends 32 and 33, respectively. The first end 32 is fixed to shaft 26 while second end 33 extends toward the sampson post 18 saddle bearing 17 combination but terminates at a point intermediate signal means 24 and the combination 1718. Second end 33 carries a swivel means 34. A second elongate means 35 having opposing first and second ends 36 and 37, respectively, is connected between swivel 34 and sampson post 18 with first end 36 being fixed rigidly to sampson post 18. As walking beam 14 oscillates up and down, signal means 24 moves therewith and shaft 26 is rotated slightly by the restraint placed thereon by elongate means 31 and 35. In this way, when the surface pumping unit is operated shaft 26 is rotated to cause a signal to be produced as described hereinabove with respect to FIG. 2.

FIG. 5 shows gear box 8 with its main shaft 9 and member 10. In this embodiment a signal means 24 is located in position 21 of FIG. 1 but behind a pulley means 40. The signal means 24 and pulley means 40 are supported on platform 7 by way of support 41. In the space between member 10 and gear box 8 is employed another pulley means 42 which is fixed to main shaft 9. A belt means 43 interconnects pulley means 40 and 42 so that operation of main shaft 9 causes rotation of shaft 26 of signal means 24 to generate a signal as explained hereinabove with respect to FIG. 2. In the situation of FIG. 5 wherein shaft 26 is rotated 360 rather than through a finite arc of less than 360 (embodiments of FIGS. 2 through 4) a conventional signal point must be put into signal means 24 so that the displacement trace will show when each 360 revolution is completed. This is known in the art and therefore will not be described in further detail.

FIG. 6 shows a top view of FIG. 5 and includes a main drive pulley 50 connected to gear box 8 by way of shaft 51. Main pulley 50 is connected to the main power source (not shown) for operating the surface pumping unit.

Reasonable variations and modifications are possible within the scope of this disclosure without departing from the spirit and scope of this invention.

We claim:

1. In a well pumping unit containing a walking beam carried by a saddle bearing which in turn is supported by a sampson post, said walking beam being driven by a main shaft from a gear box, the improvement comprising a displacement trace signal means which produces a signal upon movement of a member of said signal means and without a cable-and-reel driven device, the character of said signal varying with the extent of movement of said member, said signal means is carried by said walking beam so that movement of said walking beam can cause movement of said movable member, a first elongate member having opposing first and second ends and fixed at its first end to said movable member, said first elongate member extending generally toward said sampson post-saddle bearing combination, said and means for conducting said signal from said signal I means to a receiving means. 

1. In a well pumping unit containing a walking beam carried by a saddle bearing which in turn is supported by a sampson post, said walking beam being driven by a main shaft from a gear box, the improvement comprising a displacement trace signal means which produces a signal upon movement of a member of said signal means and without a cable-and-reel driven device, the character of said signal varying with the extent of movement of said member, said signal means is carried by said walking beam so that movement of said walking beam can cause movement of said movable member, a first elongate member having opposing first and second ends and fixed at its first end to said movable member, said first elongate member extending generally toward said sampson postsaddle bearing combination, said first elongate member terminates at its opposing second end intermediate said signal means and said combination, said second end of said first elongate means carries a swivel means, a second elongate means having opposing first and second ends and fixed at its first end to said sampson post, said opposing second end of said second elongate means being connected to said swivel means so that as said walking beam reciprocates up and down the movable member is moved by the restraint placed thereon by said first and second elongatE means, and means for conducting said signal from said signal means to a receiving means. 